#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
#define rep(i, n) for(int i=0;i<(n);++i)
#define rep1(i, n) for(int i=1;i<=(n);i++)
#define ll long long
using mint = modint998244353;
using P = pair<ll,ll>;
using lb = long double;
using T = tuple<ll, ll, ll>;
#ifdef LOCAL
#  include <debug_print.hpp>
#  define dbg(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#  define dbg(...) (static_cast<void>(0))
#endif

int main()
{
    int n;
    cin >> n;
    vector<int> a(n),b(n),c(n);
    rep(i,n) cin >> a[i];
    rep(i,n) cin >> b[i]; 
    rep(i,n) cin >> c[i];
    vector<vector<ll>> dp(n+1, vector<ll>(6));
    auto fp = dp;
    rep(i,n) {
        dp[i+1][1] = max(dp[i+1][1], dp[i][0]+a[i]);
        dp[i+1][1] = max(dp[i+1][1], dp[i][1]+a[i]);
        dp[i+1][2] = max(dp[i+1][2], dp[i][0]+b[i]);
        dp[i+1][2] = max(dp[i+1][2], dp[i][1]+b[i]);
        dp[i+1][2] = max(dp[i+1][2], dp[i][2]+b[i]);
        dp[i+1][3] = max(dp[i+1][3], dp[i][0]+c[i]);
        dp[i+1][3] = max(dp[i+1][3], dp[i][1]+c[i]);
        dp[i+1][3] = max(dp[i+1][3], dp[i][2]+c[i]);
        dp[i+1][3] = max(dp[i+1][3], dp[i][3]+c[i]);
        dp[i+1][4] = max(dp[i+1][4], dp[i][0]+b[i]);
        dp[i+1][4] = max(dp[i+1][4], dp[i][1]+b[i]);
        dp[i+1][4] = max(dp[i+1][4], dp[i][2]+b[i]);
        dp[i+1][4] = max(dp[i+1][4], dp[i][3]+b[i]);
        dp[i+1][4] = max(dp[i+1][4], dp[i][4]+b[i]);
        dp[i+1][5] = max(dp[i+1][5], dp[i][0]+a[i]);
        dp[i+1][5] = max(dp[i+1][5], dp[i][1]+a[i]);
        dp[i+1][5] = max(dp[i+1][5], dp[i][2]+a[i]);
        dp[i+1][5] = max(dp[i+1][5], dp[i][3]+a[i]);
        dp[i+1][5] = max(dp[i+1][5], dp[i][4]+a[i]);
        dp[i+1][5] = max(dp[i+1][5], dp[i][5]+a[i]);
    }
    ll ans = 0;
    rep(i,6) ans = max(ans, dp[n][i]);
    rep(i,n) {
        fp[i+1][1] = max(fp[i+1][1], fp[i][0]+a[i]);
        fp[i+1][1] = max(fp[i+1][1], fp[i][1]+a[i]);
        fp[i+1][2] = max(fp[i+1][2], fp[i][0]+b[i]);
        fp[i+1][2] = max(fp[i+1][2], fp[i][1]+b[i]);
        fp[i+1][2] = max(fp[i+1][2], fp[i][2]+b[i]);
        fp[i+1][3] = max(fp[i+1][3], fp[i][0]+a[i]);
        fp[i+1][3] = max(fp[i+1][3], fp[i][1]+a[i]);
        fp[i+1][3] = max(fp[i+1][3], fp[i][2]+a[i]);
        fp[i+1][3] = max(fp[i+1][3], fp[i][3]+a[i]);
        fp[i+1][4] = max(fp[i+1][4], fp[i][0]+b[i]);
        fp[i+1][4] = max(fp[i+1][4], fp[i][1]+b[i]);
        fp[i+1][4] = max(fp[i+1][4], fp[i][2]+b[i]);
        fp[i+1][4] = max(fp[i+1][4], fp[i][3]+b[i]);
        fp[i+1][4] = max(fp[i+1][4], fp[i][4]+b[i]);
        fp[i+1][5] = max(fp[i+1][5], fp[i][0]+a[i]);
        fp[i+1][5] = max(fp[i+1][5], fp[i][1]+a[i]);
        fp[i+1][5] = max(fp[i+1][5], fp[i][2]+a[i]);
        fp[i+1][5] = max(fp[i+1][5], fp[i][3]+a[i]);
        fp[i+1][5] = max(fp[i+1][5], fp[i][4]+a[i]);
        fp[i+1][5] = max(fp[i+1][5], fp[i][5]+a[i]);
    }
    rep(i,6) ans = max(ans, fp[n][i]);
    cout << ans << endl;
    return 0;
}